48re + superior trans parts 2nd to 3rd issue

[Mathes308]

I see this one has been hashed to death but I'm not getting concrete help.

For those of you who have superior trans stuff.
I had a trans shop install the shift kit and both low rev and 2nd gear kits.
After that I had no 2nd gear, the shop said it was because the band was down to the rivets and couldn't hold so it would redline or skip to 3rd
Ok, so I had them drop the trans and they installed the rest of the 1st/rev kit and replaced all bushings, seals, springs, washers, etc.
New borg Warner high energy clutches and bands, 2nd gear band he said has full clutch material, not the slotted.
I also had them put a low stall billet triple disk torque converter in that he said was a precision, believe he said precision of new Hampton.

So, trucks back, everything seems great except I get enough 2nd to 3rd overlap that it feels like you tap the brakes.
Trans shop said it's pretty normal and should drive it. Talked to superior transmission parts and they said it happens a lot because the spring in the second gear servo is too weak and recommended backing the adjustment screw outside off a half a turn and then another half turn if it didn't clear it up.
Well, did the half turn, seemed better, went another half turn and maybe it's a little softer, could be me wishing it though, still nods your head when going from 2nd to 3rd.
Should I go more?
Read about guys putting stiffer springs in the servo. I'm not sure where to go from here, deathly afraid of ruining something with the overlap, can't afford any more trans work.
Was suggested that the band might be grippy being new and will wear in, haven't gone more than maybe 30 miles.
Thoughts?
Oh, running Amsoil ATF in it.

Thanks.

 

[cerberusiam]

Back it off a half turn is probably too much, a full turn is too much if they had it set correctly. I would reset to stock and make sure they adjusted it correctly. TQ the screw to 72 INCH LBS and back it off 1 3/4 turns.

You might have to put 1 more turn in the line pressure adjustment and a 1/2 turn in the TV pressure adjustment to make it shift better. I did not see anything about replacing the fornt servo and\or cover which should be done. Good possibility you got a servo that is incompatible. I would verify exactly what was done there to make sure.

 

[Mathes308]

Shift kit is K48RE
The K080-MAG
And the K086 kit

He also installed all new electronics with borg warners, the gov pressure sensor is the new style borg. Not the gm though.

Superior says all parts were correct for the 03 48re

 

[cerberusiam]

Those are correct parts, just questioning if enough parts were installed. No mention of what was done to the front servo and that is where the shift timing problems usually originate, along with adjustment.

 

[Mathes308]

That's a tough one, he says he's installed a bunch of them and every time these trans's end up with overlap on the 2nd to 3rd
Even the superior trans guy said it was common and their fix was to keep backing off the screw.
I'm afraid running with overlap is going to wear the band or clutches prematurely and over stress parts.
But at least I can try resetting the screw to spec. Might take me a while, it's 10 degrees outside.

 

[cerberusiam]

If it is binding it will wear things prematurely, should not be happening. The excuse they all do it is bogus, I used the same kit and no overlap to speak of. We need to reset the pressures a bit form recommended but it is fine. We also put in a new no-leak servo hence my question about what parts were used.

 

[Mathes308]

Talked to superior again today, they said because the super servo has more apply area and the band used is a full surface band there will always be the slight drag feel to 3rd
He said without this overlap there would be a flair or slip bump to 3rd and would do damage to the 3rd gear clutches and the felt bind now will not cause wear or harm.
Asked about a stiffer servo spring or trying to time it out, he said the ONLY thing to alleviate some of the felt bind is to come out about 3-1/2 turns on the 2nd gear adjuster.
Anything else will affect 3rd.

Make sense?

 

[cerberusiam]

Did you validate for sure the super servo was installed? That is a typical problem when using the super servo and the stock 5.0 lever.

I would have to disagree on the rest, a bind will accelerate the wear on the band and it is border line at best. Any more than 2.25 or 2.5 turns on the front band adjustment and I think you run the risk of slipping the band in high TQ scenarios.

It is not the only thing to alleviate the problem, I had pretty good luck shimming the servo spring. I added 2 7/16 washers under the spring and backed the band off to 2 turns and it was pretty good at that point with what I am sure is a damaged direct clutch pack. I also went back to the stock servo with the billet cover and got the same results.

The situation is easily fixable for a few $$. I would expect your builder to step up and make this right as it is a known issue on these transmissions.

 

[Mathes308]

I looked in the box, he stuck everything back that he swapped out so the whole kit was used, the stock servo shows signs of binding on the shaft.
I would say he used the stock lever since the kit doesn't come with different ones.
I've read the 4.2 lever helps.
Superior said they don't offer a spring.
Might talk to my builder now that I have some more info and see what he thinks about trying the lever change or increasing the spring.
I know trying to live with the 2nd gear head nod is going to drive me nuts.

 

[cerberusiam]

If he replaced the servo and used one of those super servos that problem will never go away. TCS makes a new no leak servo that is the same size as stock and does not suffer from these issues.

 

[Mathes308]

Just spoke to tcs, they said the same thing, the super servo isn't needed. Too much pressure, they said to see what apply lever superior recommends with their kit and use a stock style servo like theirs.

 

[cerberusiam]

I fat fingered the reply, the TCS servo does NOT suffer from the overlap issues when used with a Superior shift kit and the stock 5.0 lever. I have one on a 48RE and it works fine, just had to adjust the initial TV and line pressure settings a bit.

If you want to stay with the super servo you will need a 4.2 or 4.4 apply lever to tune the overlap out.

 

[BILTIT]

Interesting, mine does this as well under light throttle/load. Unfortunately i have no idea what parts are in the trans.

 

[Mathes308]

Crappy options.
Drop the trans to change the lever to 4.2 and buy a lever or buy the TCS servo for $110 and hope it works with the 5.0 lever and superior kit.

Superior says their super servo works with 4.7-5.2 levers and is a "must use" in diesel applications.

Does that mean only with a stock valve body?
Is their kit then not designed to work in conjunction with their servo?

Going to read over the shift kit paperwork tonight, don't remember it saying the lever needed changed.

Sucks, can't drive it with that much bind, can't afford to keep throwing parts at it.

Also, TCS suggests a 4.2 lever with their stock size servo and cannot say if it works with a 5.0
This is also assuming mines 5.0 stock.

*sigh*

 

[cerberusiam]

Changing the servo is by far going to be the cheapest option. Check with your builder to make SURE that is what they put in before proceeding.

The TCS servo works fine with the superior kit and a 5.0 lever, given all things equal. The TCS servo is not over sized so it doesn't have the issues of the larger one. It took a little tweaking but it worked fine on the one I just finished.

 

[Mathes308]

Update.

Truck is back.
After many pan drops and adjustments he finally resorted to installing a new stock style servo and a slightly stiffer spring than stock.
Downshifts are now crisp and quick with no flare.
The 2-3 up shift feels like a stock shift with a light pause, not great but tolerable.
Guess we'll see if it's good enough to keep it alive.
Might try reducing the torque management with the smarty jr now that it has good clutches, pressure, and a precision new Hampton triple disk.

Only thing left would be a complete valve body, maybe later, bleeding money as it is.

 

[clemson726]

I know this thread is a few years old but I feel like this is the one to ask this question..... I have a 2-3 overlap since the superior shift kit/tcs servo/accumulator. I'm using the factory band lever to avoid pulling the transmission. I checked line pressure at 80psi at idle in Drive. I've loosened the band to about 2.25 turns. It felt like its now gone to the other side and instead of binding, its flaring. So now i'm thinking I'll put the band back to 2 turns out and shim the servo spring with washers. So the question is, what size washers is it? Somebody clear up my scattered mind. i see earlier 2 7/16" washers. 7/16 seems small. is that 2.4375? ID or OD. what thickness. I can make some spacers here at work. I just need to know what they are. They go between the cover and the spring?

 

[cerberusiam]

Yeah, they go between the cover and the spring. In you can make spacers you can get a lip on them to hold centered. That is a 2 + 7/16 wide washer or 2.4375 as you noted. You cna build your spacers more exact but you need the spring and cover to do it.